Endocavitary ultrasound probe with biopsy system having two needle guides

ABSTRACT

A biopsy assembly for collecting tissue samples by means of a biopsy needle when introduced in a body cavity. The biopsy assembly comprises an elongated member ( 101 ), with a longitudinal axis ( 102 ), configured with: a first needle guide ( 203 ), arranged to guide a needle in a direction transverse to the longitudinal axis ( 102 ), and a second needle guide ( 204, 303 ) arranged to guide a needle in a direction along the elongated member ( 101 ).

BACKGROUND

Various ultrasound techniques and devices have been developed forimaging the interior of a body e.g. the human body. One application ofultrasound imaging has been in the medical field, and in particular, inendocavitary probes (e.g., biopsy guidance endocavitary probes). Suchprobes may be used, for example, for endovaginal examination (e.g., toexamine the uterus, ovaries, etc.), endorectal examination (e.g., toexamine the rectal wall, prostate, etc.), and/or other medically-relatedapplications. It should be noted that for instance endorectalexamination is rather unpleasant and that biopsy taking is ratherpainful and therefore typically requires local anaesthesia.

Endocavitary probes typically have an elongated rod-like shapeconfigured with a handle that extends as a portion of the elongatedrod-like shape, but in the end opposite the distal end. Other ultrasoundprobes are, contrary to endocavitary probes, configured for placing theprobe on the skin of the body to provide imaging of the interior of thebody located beneath the skin. Still other probes (e.g. intra-operativeprobes) are configured for placing the probe directly on organs insidethe body during surgery operations.

RELATED PRIOR ART

JP 02071732-A discloses an elongated ultrasound probe for biplaneultrasound imaging of a prostate. The elongated probe comprises an endportion with a longitudinally arranged transducer array for sagittalimaging and a transversely arranged transducer array for transverseimaging, where the longitudinally arranged array is placed perpendicularto the transversely arranged array, but on the more distal end of theend portion, such that the image planes of the two transducers intersectorthogonally. The arrays are formed in a convex arc shape so as toprovide the image planes from radial scan lines. The arc shapes have arelatively smooth shape.

The ultrasound probe is disclosed interconnected with a biopsy needleguide configured for guiding a biopsy needle longitudinally to theelongated ultrasound probe, but offset a certain distance from theprobe. The biopsy needle guide is configured such that the biopsy needleis guided through the opening of the body cavity and penetrates the bodyfrom the interior of the body cavity.

U.S. Pat. No. 6,443,902-B1 discloses an ultrasound probe with adetachable needle guide for collecting tissue samples. The ultrasoundprobe is configured for insertion into a body cavity and comprises twotransducer arrays and a needle guide assembly for guiding a biopsyneedle. The transducer arrays are arranged perpendicular to each otherlike described above, so as to provide bi-plane imaging.

The needle guide assembly is separate from, but can be interconnectedwith the ultrasound probe. The ultrasound probe can be covered by a softsheath and the needle guide assembly can then be attached to the probe,but such that the sheath prevents contact between the probe andassembly. Thus, the needle guide is arranged outside the sheath in sucha manner that a needle of the needle guide need not penetrate thesheath. Thereby, only the assembly, but not the probe needssterilization after use. The needle guide is arranged to guide theneedle in a direction transverse to a longitudinal axis of the elongatedultrasound probe. The biopsy needle guide is configured such that thebiopsy needle is guided through the opening of the body cavity andpenetrates the body from the interior of the body cavity.

U.S. Pat. No. 6,261,234-B1 discloses a probe for providing simultaneousviewing of an instrument in two ultrasound imaging planes (biplaneinstrument guidance).

The probe is configured as an elongated member with an end-portion thatis configured to accommodate two transducer arrays. The two transducerarrays are in the form of a side-fire transducer array and end-firetransducer array arranged along a respective convex arc shape to providetwo imaging planes. The two imaging planes intersect at a line whichcoincides with an instrument path. A needle guide in the form of agroove of the probe is arranged to guide the needle along the instrumentpath when it protracts from the groove. Seen towards the end-portion,the transducer arrays are arranged in an L-shaped configuration, wherethe groove has an opening, wherefrom the needle protracts, at the cornerof the L-shape.

Despite the above prior art documents disclosing important improvements,the cited prior art documents do not fully take advantage of thepossibilities related to patient comfort and effectiveness/efficiency inmedical diagnosis situations.

A known configuration comprises a biopsy needle guide for guiding aneedle a long a path longitudinal to, but offset from a rod-shaped probeand a side-fire monitoring of the path (cf. U.S. Pat. No. 6,443,902-B1,FIG. 1). However, this configuration poses problems when used for takingbiopsies of a prostate. A biopsy regimen can include e.g. at least twobiopsies from the apical area of the prostate (closest to the pelvicfloor muscles). In this situation the biopsy needle will first penetrateinto the human tissue at a small, but sometimes significant distancebehind the sagittal image projection which projects from the firsttransducer. Examining the anatomy slightly below the apex more closelyidentifies the different pelvic floor muscles. It is then clear that anyattempt to introduce a biopsy needle along, but offset from the probewill cause the needle to come close to—or even pass through parts of themuscles which is painful.

SUMMARY OF THE INVENTION

Therefore, expediently, a needle guide is arranged to guide a needle ina direction transverse to the longitudinal axis, and a second needleguide is arranged to guide the needle in a direction along the elongatedmember.

The transversely guided biopsy needle is thus guided through the openingof the body cavity and penetrates the body from the interior of the bodycavity. Thereby, the basal area of the prostate can be sampled by biopsywhile being safely monitored by the side-fire imaging. Thelongitudinally guided biopsy needle is also guided through the openingof the body cavity (very close to the periphery of the probe) andpenetrates the body from the interior of the body cavity. Likewise, butwhen rotated about 90 degrees and introduced into the body at a steeperangle, the apical area of the prostate can be sampled by biopsy.Thereby, the prostate apex and basal can be sampled by biopsy in thesame cycle.

The combination of the transversely guided biopsy needle andlongitudinally guided biopsy needle provides a superior probe for takingbiopsies of a prostate in a single cycle of operations.

Preferably, the first needle guide is arranged to provide an anglebetween the needle, when inserted into the needle guide, and thelongitudinal axis of the elongated member within the range of 10 to 50degrees. The needle guide can be shaped as a substantially straight tubeor curved tube.

Preferably, the first needle guide provides an angle of a needle, wheninserted into the first needle guide, at its projection from the firstneedle guide and the longitudinal axis of the elongated member withinthe range of 10 to 50 degrees. The projection of the needle can becontrolled by the needle guide to obtain the desired angle ofprotraction.

Expediently, the needle guides are arranged, with respect to theelongated member, to make the needles, when inserted into the needleguides, protract at opposite positions with respect to a cross-sectionof the biopsy assembly. Thereby, the relevant locations for takingsamples of the tissue under examination can be addressed by the paths ofthe biopsy needles by firstly using the first needle guide to take firstbiopsies (removing the biopsy needle) and then simply rotating the probeto take second biopsies. This is far more convenient than actuallychanging probe.

In a preferred embodiment, the second needle guide extends along theperiphery of the elongated member, but offset from the periphery in adirection away from the point of gravity in a cross-sectional view ofthe elongated member.

In a preferred embodiment, the elongated member has a shape that isconfigured for mechanical interconnection with a probe and to match arecess of a probe so as to provide a combination of the assembly andprobe, when interconnected, that can be circumscribed by a cylinder thatcovers at least a portion of the length of the elongated member and hasa diameter that is within the range of 12 to 30 millimetres.

The elongated member is configured with coupling means forinterconnection with an ultrasound probe with complementary couplingmeans.

The needle guides may be shaped as a tube with an entry end configuredfor entry of a needle and an exit end configured for the needle toproject from the needle guide. The smooth shape of a tube has a smallertendency to collect dirt and remainders of tissue, since there are fewerprotrusions.

To reduce the risk of confusing the acquired images, marking on biopsyneedle guides may correspond to marking of acquired bi-plane images,respectively, when displayed on a display screen.

There is also provided an ultrasound probe for cavity scanning of a bodyand for guiding a biopsy needle. The ultrasound transducer is configuredwith: an ultrasound transducer to provide an imaging plane; a firstneedle guide configured to guide an elongated needle and arranged toguide the needle in a direction transverse to the longitudinal axis, anda second needle guide configured to guide an elongated needle andarranged to guide the needle in a direction longitudinal to theelongated member.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments will be described in greater detail and withreference to the drawing in which:

FIG. 1 shows a cross-sectional view of an ultrasound probe comprising atransducer array with a field of view;

FIG. 2 shows a cross-sectional view of an ultrasound probe comprising aneedle guide arranged longitudinally and a needle guide arrangedtransversely;

FIG. 3 shows a cross-sectional view of an ultrasound probe comprising aneedle guide arranged along the ultrasound transducer, but inclined;

FIG. 4 shows a cross-sectional view of an ultrasound probe in a modeproviding sagittal side-fire imaging and a transverse imaging;

FIG. 5 shows a cross-sectional view of an ultrasound probe in a modeproviding sagittal end-fire imaging;

FIG. 6 shows a cross-sectional view of an ultrasound probe shown withdifferent field of views;

FIGS. 7a-b show a side-view and a top-view of an ultrasound probe with arecess for accommodating a biopsy assembly;

FIGS. 7c-d show a top view and a side-view of a biopsy assembly;

FIG. 7e shows an interconnected ultrasound probe and biopsy assembly;

FIG. 7f shows an ultrasound probe protected by a cover;

FIG. 7g shows a biopsy assembly with a curved needle guide;

FIGS. 8a and 8b show a side-view and a 3D view of an ultrasound probe ina biplane mode;

FIGS. 9a and 9b show a side-view and a 3D view of an ultrasound probe inan end-fire mode; and

FIGS. 10a and 10b show a side-view and a 3D view of a biopsy assembly.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows a cross-sectional view of an ultrasound probe comprising atransducer array with a field of view. The ultrasound probe 100 isconfigured for cavity scanning of a body in that it has an elongated orrod-like shape which can be introduced into the cavity. In general suchan ultrasound probe has a handle, a shaft and a distal end configured toaccommodate an ultrasound transducer 104 a; 104 b. Only the portion ofthe shaft towards the distal end is shown—the handle is not shown. Thedistal end, of the probe may also be denoted a scanning head or thescanning end of the probe. The probe or rather the distal end of it mayalso be seen as a housing in that it accommodates transducer array. Ingeneral the probe has the shape of an elongated member.

A longitudinal axis 102 of the probe or elongated member is shown as adashed line. A transverse axis 103 perpendicular to the longitudinalaxis 102 is also shown as a dashed line.

In one aspect, the probe 100 is configured to accommodate at its distalend a first transducer in the form of two detached arrays 104 a;104 b ofultrasound transducer elements. The two arrays 104 a;104 b are arrangedin extension of one another, but at an offset distance in the directionof extension. However, the offset distance may be so small that thearrays provide imaging corresponding to a single array. In anotheraspect, as described further below, the first transducer is in the formof a single array. The arrays or array provide(s) an imaging planecoinciding with the longitudinal axis 102 and transverse axis 103 i.e.the axes lies in the imaging plane. For medical uses, this imaging planeis also denoted a sagittal imaging plane.

The transducer arrays 104 a,104 b are shaped so as to provide a desiredfield of view in the sagittal imaging plane. It is in general desired touse small (i.e. short) arrays. Consequently, the arrays are shaped alonga convex arc shape to emit and receive ultrasound wave energy alongradial scan lines. The radial structure of the scan lines provides asector of a circle which becomes broader with the distance to thetransducer. The smaller the radius of the convex arc shape, the broaderthe sector of the circle. The above is based on a circular arc shape.However, other arc shapes that provide radial scan lines can be used.Such other arc shapes can comprise sections of straight linear arrayseach comprising a number of transducer elements. Complex arc shapescomprising sections with, different radiuses can also be applied toobtain a desired field of view.

Since in general small clearance or close contact between the transducerand the housing of the distal end is desired, the shape of thetransducer dictates the shape of the housing about the transducer. Inthe shown configuration, the housing and the transducer have the shapeof a portion of a circular arc. Since it is an objective to provide adesign of the probe which is suitable for cavity scanning and thus forsuitable for being introduced into the cavity, the probe has adepression 106 behind the housing that accommodates the transducerarrays 104 a,104 b. Thereby the field of view 105 a about the transverseaxis 103 is allowed to extend further towards the handle end of theprobe without requiring a larger diameter of the housing.

The arrays 104 a and 104 b of the first transducer provide partialfields of view 105 a and 105 b, respectively. The field of view 105a,105 b provided by the first transducer 104 a,104 b covers more than 15degrees of scan lines at each side of its intersection with thelongitudinal axis 102 and more than 15 degrees of scan lines at eachside of its intersection with a transverse axis 103. Thus angles a1, a2,a3 and a4 are larger than 15 degrees. The angles need not be equal in apreferred embodiments a1 plus a2 is approximately equal to a3 plus a4.

For most practical purposes a partial field of view of more than 30degrees is desired. Thus, preferably, the field of view, at each side ofits intersection with the longitudinal axis or transverse axis, covers aradial section larger than an angle selected from the group of 20, 25,30, 35, 40, 45, 50 and 55 degrees.

It is shown that the first transducer has partial fields of view whichare centred about the longitudinal axis 102 and the transverse axis 103.It is also shown that the field of view 105 b established about thelongitudinal axis 102 and the field of view 105 b established about thetransverse axis 103 are of substantially same size.

FIG. 2 shows a cross-sectional view of an ultrasound probe comprising aneedle guide arranged longitudinally and a needle guide arrangedtransversely. This arrangement of the needle guides enhances the use ofthe ultrasound probe to be used for taking biopsy samples along twodifferent biopsy paths while providing safe monitoring of both thepaths.

The transverse needle guide 203 and longitudinal needle guide 204 can,as shown, be integrated with the probe body 101. Alternatively, asdescribed further below, the probe can be configured with coupling meansfor interconnection with a biopsy assembly with complementary couplingmeans.

The probe body 101 comprises a first, transverse needle guide 203configured to guide a needle along a path 202 which intersects with thefield of view 105 a established about the transverse axis 103. Itfurther comprises a second, longitudinal needle guide 204 configured toguide a needle along a path 201 which intersects with the field of view105 b established about the longitudinal axis 102. Thereby, a needle orother instrument guided, by means of the needle guide, along one of thepaths will intersect with at least some of the scan lines of therespective fields of view and thus be viewable during the ultrasoundscanning. Thereby safe monitoring of both the paths is provided.

The transverse needle guide 203 guides a needle along the path 202. Thispath intersects the scan lines of the field of view 105 a establishedabout the transverse axis 103 at angles say between about 25 to 90degrees. Thereby, the path 202 is viewable across the entire field ofview.

The transverse needle guide is arranged to provide an angle between theneedle, when inserted into the needle guide, and the longitudinal axisof the elongated member within the range of 10 to 50 degrees, preferablyat about 15 to 20 degrees e.g. at 17 degrees.

For a straight transverse needle guide, the same angle is provided alongthe entire path 202. But a needle guide configured to provide a curvedpath can also be employed. Such a curved guide can provide an angle of aneedle, when inserted into the first needle guide, at its projectionfrom the first needle guide and the longitudinal axis of the elongatedmember within the range of 10 to 50 degrees. Generally, the curved pathis configured with a curvature larger than 20 millimetres and/or 25millimetres and/or 30 millimetres and/or 35 millimetres and/or 40millimetres. Thereby it is possible to guide a biopsy needle, which isconfigured with sufficient strength and volume to take out a biologicalsample and hence has only a limited flexibility.

The longitudinal needle guide 204 guides a needle along the path 201.This path intersects the scan lines of the field of view 105 bestablished about the longitudinal axis 102 at angles say between about5 to 25 degrees. Thereby, the path 201 is viewable only at a partialsector of the field of view.

Seen along the longitudinal axis 102 at a point more distal than thehousing of the probe and towards the housing of the probe, the needleguides are arranged, with respect to the elongated member, to make theneedles, when inserted into the needle guides, protract at oppositepositions with respect to a cross-section of the biopsy assembly. Thus,e.g. a prostate can be addressed by either one of the paths 201,202 byrotating the probe 180 degrees about its longitudinal axis.

In this embodiment, the first transducer is configured as a single array104. Thereby, the signals to and from the elements of the transducerarray can be elected electronically so as to provide differently sizedor positioned images from the transducer array. This will be explainedin greater detail further below.

FIG. 3 shows a cross-sectional view of an ultrasound probe comprising aneedle guide arranged along the ultrasound transducer, but inclined. Inthis embodiment, one of the needle guides 303 extends in a directionalong the elongated member 101. This direction may be parallel to alongitudinal axis of the elongated probe or, as shown, inclined withrespect to a longitudinal axis of the elongated probe. This inclinationis preferably arranged such that the path 302 crosses the longitudinalaxis in front of the transducer 104. The needle guide 303 can beconfigured as a straight channel or a curved channel. Thus, theinclination need not be present—or be the same—along the entire lengthof the guide 303.

FIG. 4 shows a cross-sectional view of an ultrasound probe in a modeproviding bi-plane imaging. The bi-plane imaging is provided by sagittalside-fire imaging and transverse imaging. The transverse imaging isprovided by a second transducer array 405 to provide a second imageplane 406 transverse to the longitudinal axis of the elongated member.Preferably, the second image plane 406 is orthogonal to the first imageplane 407. The second image plane is also denoted the transverse imageplane.

The transverse image plane 406 may be arranged so as to coincide withthe axis 103 transverse (perpendicular) to the longitudinal axis 102i.e. at right angles or about right angles. However, as shown, it ispreferred that the second transducer array is inclined to provide thetransverse image plane at an angle of less than 90 degrees with respectto the longitudinal axis towards the distal end of the elongated member.The transverse image plane 406 is shown at an angle of about (180degrees minus 107 degrees equal to) 73 degrees relative to thelongitudinal axis 102. Preferably, the second transducer is inclined toprovide the second image plane at an angle that is within the range of40 to 85 degrees with respect to the longitudinal axis towards the oneend of the elongated member.

As the second transducer 405 is arranged in an inclined position closeto the first transducer 104, the image plane 406 provided by the secondtransducer intersects the field of view provided by the firsttransducer. Thereby, since some spatial locations appear in both imagingplanes, the ability provided by the second imaging plane 408 to scanoutside the sagittal imaging plane 407 can improve spatial locationdetermination. As it can be seen, the transverse field of view willintersect only scan lines of a sector the first field of view i.e. apartial sector of the first field of view.

As it is shown, the first transducer 104 is arranged at the one end ofthe elongated member 101, but on the more distal portion of the end thanthe second transducer array 405.

It is also shown that only a portion (i.e. a 131.7 degrees sectorclosest to the transverse array 405) of the first transducer 104 is usedfor providing the sagittal field of view i.e. the portion enclosed bythe depicted field of view 407. The remaining portion of the firsttransducer 104 may or may not be used when the probe is in a mode wherebi-plane imaging is provided.

In this embodiment the transverse needle guide comprises a channel 203which extends at its distal end into a projection 404. The longitudinalneedle guide comprises a channel 401 which extends at its distal endinto a projection 402. An instrument e.g. needle follows the path 403.

Preferably, the distal opening of the channel 203 is located relative tothe (left side boundary of the) field of view 407. Thereby, the path 202can be monitored/scanned when the needle starts to protract from theopening of the channel 203 and could potentially damage tissue or organsof a body.

The angle b designates the inclination of the transverse field of view406 relative to the left boundary of the (sagittal) image plane (407).The angle c designates the coverage of the (sagittal) field of view 407.The angle d designates the angle between the longitudinal axis and theleft boundary of the (sagittal) image plane (407).

FIG. 5 shows a cross-sectional view of an ultrasound probe in a modeproviding sagittal end-fire imaging. In this mode another portion of thefirst transducer array is used for acquiring the image (image signals).The end-fire image is provided from a field of view corresponding to asector of a circle of about 140 degrees. The field of view 501 issubstantially centred about a longitudinal axis 102 of the probe 101.However, this centring may deviate about ±4 degrees as the elements ofthe array may be located such that perfect centring is inconvenient. Theangle a designates the coverage of the sagittal end-fire view 501.

The probe can be operated in one of two modes: one mode providing sidefire imaging or bi-plane imaging comprising side-fire imaging andanother mode providing end-fire imaging. Preferably the probe isconfigured to enable selection of a first mode wherein an end-view imageis acquired from a first portion of the first transducer array with afield of view that covers scan lines at each side of the longitudinalaxis. It is possible to shift to a second mode wherein a side-view imageis acquired from a second portion of the first transducer array with afield of view that covers scan lines at each side of the transverseaxis. In the second mode the transverse image is also acquired. Themodes can be selected either by operating one or more buttons on theprobe or at the image-processor console.

FIG. 6 shows a cross-sectional view of an ultrasound transducer shownwith different fields of views. Four different fields of views in thesagittal image plane obtainable by the first transducer is shown. Twoend-fire fields of views and two side-fire fields of views are shown.

A first end-fire view 601 has a broader angular coverage than a secondend-fire view 602. The first end-fire view 601 covers a circular sectionof about 132 degrees. The second end-fire view 602 covers a circularsection of about 84 degrees.

A first side-fire view 604 has a broader angular coverage than a secondside-fire view 603. The first side-fire view 604 covers a circularsection of about 90 degrees. The second end-fire view 602 covers acircular section of about 132 degrees.

The second end-fire view 602 and the second side-fire view 603 arepositioned next to each other and have in combination a non-overlappingcoverage. If these side-fire and end-fire views are the desired viewsfor all uses of the probe, the first array 104 need not cover a largerfield of view. However, these side-fire and end-fire views may alsorepresent electronically selected fields of views from the—larger—fieldof view provided by the first transducer.

The first end-fire view 601 and the first side-fire view 604 arepositioned such that they establish a common field of view or overlap.This may be desired in any event since the common field of view improvesthe ability to keep a reference location when switching from theside-view to the end-view and vice versa. However, this may also be sosince the field of view provided by the first transducer array has alimited length. Thus, the fields of view (or sectors) are arranged tocover a common sector of scan lines.

The angle f designates the angle between the longitudinal axis and theleft side boundary of the (sagittal) field of view 603 and the angle gdesignates the angle between the longitudinal axis and the left side ofview 601. Angle h designates the coverage of view 601.

The probe will typically comprise electronic circuitry configured with amultiplexer for a combined parallel and time-multiplexed output of imagedata.

FIG. 7a-b shows a side-view and a top-view of an ultrasound probe with arecess for accommodating a biopsy assembly. In this embodiment, thebiopsy assembly comprises the needle guides and is detachable from theultrasound probe 700. The probe comprises an elongated shaft 702 with arecess 703 and a distal end with a housing 701 configured to accommodatethe transducer arrays (not shown). The housing 701 (or scanner head)constitutes a portion of the probe 700. As shown the housing 701 has across-section which matches the cross-section of the shaft so as to forma probe with no sharp protrusions. The housing 701 has portions orwindows 704,705 behind which the transducer arrays are mounted. Thewindows are optimized for transmission of ultrasound between thetransducers and the medium to be scanned that surrounds the probe duringuse.

An indentation or notch 715 provides a fixation hole of the assembly.

FIGS. 7c-d show a top-view and a side-view of a biopsy assembly. Thebiopsy assembly 706 comprises the needle guides and is detachable fromthe ultrasound probe 700.

The biopsy assembly 706 has an elongated member 707 with a cross-sectionin the shape of a half-section of a tube (e.g. a semi-cylindricalmember). This cross-section of the elongated member matches the recess703 of the probe so as for the assembly to be interconnected with theprobe and form an interconnected probe and assembly which is relativelysmooth and which is relatively closely interconnected such that largerslits or slots between the probe and assembly are avoided.

A collar 708 provides fixation of the assembly at the handle-end of theprobe. At the opposite end of the elongated member a knob or pin 716,when engaging with the notch 715, provides locking of the assembly atthe distal end of the probe. Retention is further improved by an upperlip 709 and a lower lip 711 which engage with a portion of the peripheryof the probe.

The upper lip 709 and lower lip 711 are configured with openings 710 and718 wherefrom instruments inserted into the channels 717 and 712 canprotract to follow the biopsy paths into the tissue under examination.

The needle guide 712 extends along the periphery of the elongated member707, but offset from the periphery in a direction away from the point ofgravity in a cross-sectional view of the elongated member. This offsetdistance is only about a few millimetres or a fraction of a millimetre.As shown this offset distance can very along the length of the elongatedmember 707.

The channels are made from a material that can stand sterilization andis robust to damage caused by a sharp instrument introduced in the guidee.g. high quality stainless steel or a suitable plastic material thatcan stand autoclaving or for disposable (single use) biopsy guides orassemblies a plastic material that can stand sterilization by gas orradioactive radiation. The channel 712 is held in a fixed positionrelative to the elongated member by means of a fixture 714.

The elongated member is made from a material that can stand autoclaving.

The channels 717 and 712 terminate at the handle-end in respectiveend-pieces 719 and 720 which are shaped as a convex cylinder for theoperator of the probe to place two fingers and securely (single-handed)maintaining the finger grip when the instrument or needle is to beintroduced into the guide. The end-pieces may optionally have a tactilesurface on a portion of surface to facilitate secure handling.Preferably, marking on the end-pieces corresponds to marking of thebi-plane images acquired by means of the first transducer in side-firemode and end-fire mode, respectively, when displayed on a displayscreen.

FIG. 7e shows an interconnected ultrasound probe and biopsy assembly. Itcan be seen that the collar 708 and upper lip 709 and lower lip 711engage with the probe. It can further be seen that the knob or pin 716engages with the notch 715 to form a locking mechanism.

FIG. 7f shows an ultrasound probe protected by a cover. The assembly isdetached from probe, but is shown next to the probe. The probe iscovered by a cover 720 such that the probe is protected from directcontact with the patient when introduced into a body cavity. Therebydisinfection of the probe after use is not needed. The probe is readyfor its next use after common cleaning thereof (when the cover 720 hasbeen removed). Thereby, the assembly 706 does not need to come intodirect contact with the probe. Arranging the assembly in this manner isparticularly advantageous in that a needle will not penetrate the cover720. As a result the probe is not unnecessarily contaminated and thusneed not be disinfected after each use.

FIG. 7g shows a biopsy assembly with a curved needle guide. In thisembodiment the transverse guide 721 is shown as a guide with a curvedchannel. Thereby, the angle of protraction can be arranged with fewerconstraints than a straight channel. Especially, the handle-end of theguide can be placed with fewer constraints thus allowing a moreergonomic or operator friendly design. Reference numerals 722 and 723designate paths of the needles guided through the transverse andlongitudinally extending needle guide, respectively.

FIGS. 8a and 8b show a side-view and a 3D view of an ultrasound probe ina bi-plane mode. The probe comprises a handle 801 and a shaft 802 with ascanning head 803. The handle has two buttons 805 for shifting betweenmodes of the probe e.g. one of the buttons selects the end-fire mode andthe other selects the bi-plane mode. At the handle-end a cableconnection 804 is provided.

The probe is interconnected with a biopsy assembly with an elongatedmember 815 which is maintained interconnected with the probe by means ofa clamp 806. An upper lip 811, a lower lip 810, a longitudinal guidechannel 809 and end-pieces 808 thereof is also shown. Further, anend-piece 807 of a transverse guide is also shown and the biopsy path812 established by the transverse guide is also shown.

The probe is shown in a mode that provides bi-plane imaging with asagittal field of view 813 and a transverse field of view 814. Thesagittal field of view 813 is arranged to provide primarily a side-fireview.

FIGS. 9a and 9b show a side-view and a 3D view of an ultrasound probe inan end-fire mode. The sagittal field of view 816 is arranged to provideprimarily an end-fire view. The biopsy path 817 established by thetransverse guide is also shown.

FIGS. 10a and 10b show a side-view and a 3D view of a biopsy assembly.This assembly is the biopsy assembly shown interconnected with the probeon FIGS. 8 and 9, but here shown in greater detail.

The biopsy assembly 1000 has an elongated member 815. A collar 818provides retention or fixation of the assembly at the handle-end of theprobe. At the opposite end of the elongated member a knob or pin 817provides retention or fixation of the assembly at the distal end of theprobe. Retention is further improved by an upper lip 811 and a lower lip810 which engage with a portion of the periphery of the probe.

The upper lip 811 and lower lip 810 are configured with openings (notshown) wherefrom instruments inserted into the channels 816 and 809 canprotract to follow the biopsy paths into the tissue under examination.

The needle guide 809 extends along the periphery of the elongated member815 and is held in a fixed position in the handle-end by a fixationprotrusion 819. The needle guide 816 extends transverse to thelongitudinal axis of the elongated member 815 and is held in a fixedposition in the handle-end by a duct 820 in the elongated member 815.The duct 820 fixates the guide by friction. At the opposite ends of theguides 816,809, the guides are fixated by the upper lip 811 and lowerlip 810.

The channels 816 and 809 terminate at the handle-end in respectiveend-pieces 807 and 808 which are shaped as a convex cylinder for theoperator of the probe to place two fingers and securely (single-handed)maintaining the finger grip when the instrument or needle is to beintroduced into the guide. Preferably, marking on the end-piecescorresponds to marking of acquired bi-plane images, respectively, whendisplayed on a display screen. As shown the end-pieces can have adifferent outer shape e.g. an outer shape as concave cylinder (807) oran outer shape as a combined cylinder and cone.

It should be noted that the elongated member (101) can a rod-shapedmember e.g. as shown on FIGS. 1 to 5. However, the elongated member neednot accommodate an ultrasound transducer. Consequently, the depression106 is not needed.

The invention claimed is:
 1. A biopsy assembly, comprising: a semicylindrical elongated member; including: a longitudinal axis, a firstend at one of two ends of the semi cylindrical elongated member, asecond end at the second of the two ends of the semi cylindricalelongated member which is opposite the first end along the longitudinalaxis, a first side extending between the two ends along the longitudinalaxis, and a second side extending between the two ends along thelongitudinal axis; wherein the first side is opposite the second sideacross the longitudinal axis; a first needle guide structure thatextends in a first direction transverse to the longitudinal axis of thesemi cylindrical elongated member from the first side at the first end,through a material free region of the semi cylindrical elongated member,to the second side at the second end; wherein the material free regionis between the first side and the second side, and a second needle guidestructure that extends in a second direction along the longitudinal axisof the semi cylindrical elongated member between the first end and thesecond end and outside of the outer perimeter of the semi cylindricalelongated member.
 2. The biopsy assembly of claim 1, further comprising:a retention protrusion extending from the second end in a directionalong the longitudinal axis of the semi-cylindrical elongated member. 3.The biopsy assembly of claim 1, further comprising: a semi-cylindricalretention collar disposed about an outer perimeter of the first end ofthe semi-cylindrical elongated member.
 4. The biopsy assembly of claim3, further comprising: a probe clamp disposed about an outer perimeterof the first end of the semi-cylindrical elongated member, includingabout the semi-cylindrical fixation collar.
 5. The biopsy assembly ofclaim 1, further comprising: an upper lip disposed at the second side ofthe second end and including an opening to an end of the first needleguide structure.
 6. The biopsy assembly of claim 1, further comprising:a lower lip disposed at the second side of the second end, extendingfrom the second end in a direction along the longitudinal axis, andincluding one or more openings to an end of the second needle guidestructure.
 7. The biopsy assembly of claim 1, wherein the second needleguide structure includes an end-piece extending from the first end inthe direction along the longitudinal axis and a longitudinal guidechannel that terminates at the end-piece.
 8. The biopsy assembly ofclaim 7, further comprising: fixation protrusion of the semi-cylindricalelongated member configured to support the second needle guide structureat a fixed position.
 9. The biopsy assembly of claim 1, wherein thefirst needle guide structure includes an end-piece extending from thefirst end in a direction transverse to the direction of the longitudinalaxis and a longitudinal guide channel that terminates at the end-piece.10. The biopsy assembly of claim 1, further comprising: a duct of thesemi-cylindrical elongated member configured to support the first needleguide structure at a fixed position.
 11. The biopsy assembly of claim 1,wherein the material free region is between the first side and thesecond side.
 12. The biopsy assembly of claim 1, where the first sideincludes a first outer surface and a first inner surface, the secondside includes a second outer surface and a second inner surface, and thematerial free region is between the first inner surface and the secondinner surface.
 13. The biopsy assembly of claim 1, where the firstneedle guide structure intersects the longitudinal axis.
 14. Anultrasound probe, comprising: a shaft; a handle disposed at a proximalend of the shaft; a scanning head disposed at a distal end of the shaft;and a biopsy assembly of a needle guide disposed about the shaft, theneedle guide including: a semi cylindrical elongated member; including:a longitudinal axis, a first end at one of two ends of the semicylindrical elongated member, a second end at the second of the two endsof the semi cylindrical elongated member which is opposite the first endalong the longitudinal axis, a first side extending between the two endsalong the longitudinal axis, and a second side extending between the twoends along the longitudinal axis; wherein the first side is opposite thesecond side across the longitudinal axis; a first needle guide structurethat extends in a first direction transverse to the longitudinal axis ofthe semi cylindrical elongated member from the first side at the firstend, through a material free region of the semi cylindrical elongatedmember, to the second side at the second end; wherein the material freeregion is between the first side and the second side, and a secondneedle guide structure that extends in a second direction along thelongitudinal axis of the semi cylindrical elongated member between thefirst end and the second end and outside of the outer perimeter of thesemi cylindrical elongated member.
 15. The ultrasound probe of claim 14,further comprising: an upper lip disposed at the second side of thesecond end and including an opening to an end of the first needle guidestructure, wherein the upper lip is configured to physically engage aportion of a periphery of the shaft.
 16. The ultrasound probe of claim15, further comprising: a lower lip disposed at the second side of thesecond end, extending from the second end in a direction along thelongitudinal axis, and including one or more openings to an end of thesecond needle guide structure, wherein the lower lip is configured tophysically engage a portion of a periphery of the shaft.
 17. Theultrasound probe of claim 14, further comprising: a duct of thesemi-cylindrical elongated member configured to support the first needleguide structure at a fixed position, wherein the duct is configured toapply a frictional force to fixate of the first needle guide structureat the fixed position.
 18. The ultrasound probe of claim 14, furthercomprising: a fixation protrusion extending from the second end in adirection along the longitudinal axis of the semi-cylindrical elongatedmember; a semi-cylindrical fixation collar disposed about an outerperimeter of the first end of the semi-cylindrical elongated member; anda probe clamp disposed about an outer perimeter of the first end of thesemi-cylindrical elongated member, including about the semi-cylindricalfixation collar.